The long term goal of this project is to determine the role played by amino acid transmitters in the development of sexually differentiated brain processes. Research in rats has demonstrated that gonadal steroids exert broad influences on amino acid transmission and these transmitters are in turn integral regulatory components of various reproductive parameters including patterns of gonadotropin secretion and sex-typical behaviors. There are sex differences in aspects of amino acid transmission in adult rat brain but whether these differences are the result of sexual differentiation of the brain during the sensitive perinatal period is unknown. Furthermore, whether amino acid transmitters play a role in the differentiation process per se, has not been investigated.